Human and animal variolae : a study in comparative pathology / by George Fleming.

  • Fleming, George, 1833-1901.
Date:
1881
Catalogue details

Licence: Public Domain Mark

Credit: Human and animal variolae : a study in comparative pathology / by George Fleming. Source: Wellcome Collection.

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    Deeply impressed with the vast importance of arriving at the truth in such? a grave question, I have for many years devoted much attention to it, and have already done what in me lay to settle it : at least so far as the Variolas of animals are concerned, as will be seen on referring to my work on <c Vet¬ erinary Sanitary Science and Police ” (vol. ii., p. 28) ; and I will now venture to dispute every one of the arguments brought forward to prove that human Variola and Cow-pox are due to the same virus, or are the same disease ; or that there are only Small-pox and Sheep-pox as distinct Variolas. With regard to animals, I may at once state that I believe every species has its own in¬ dependent and particular kind of Variola, and I am unable to understand why man and the sheep should alone have the unhappy privilege of being the special subjects of different forms, and this privilege be denied to all the other creatures. Whether these forms may have been originally derived from a common or primitive source or type, I will not now stop to inquire ; but that they exist and compose a group of diseases rather than one malady, cannot be matter for doubt. That they more or less widely differ from each other, that in each species each form has a special character, and though that which is particu¬ lar to one species may be transmitted to another species, yet the Variola of this species need be scarcely a subject for dispute ; while the fact that their differences are marked, not only with regard to their particular features, but also as to their capability of transference to other species, and their antagon¬ ism to each other, has been clearly demonstrated. Admitting that which I shall presently attempt to prove, that the cow has its own Variola, we know that when this is communicated to man it does not produce Small-pox, though it protects from it. The Sheep-pox has been inoculated on man by many experimenters—among others, by Marchalli, Sacco, Voison, and Hering, but only a small localised group of pustules, quite unlike the eruption of ovine Variola, has appeared at the seat of inoculation, and no protection from Small-pox or Vaccinia has been conferred. Neither human Variola or yet Vaccinia will give rise to Sheep-pox, neither will their inoculation protect the sheep from its own Variola. Horse-pox is communicable to the cow and mankind, and protects them from their Variolae, as well as the human species from Vaccinia, while vaccination protects the horse from its Pox. As we shall see immediately, though the virus of human Small-pox, when deposited in the skin of the cow, does give rise to a local papulation—often very trifling, exceptionally very marked—yet this is not the regular eruption of Cow-pox,, either in its appearance or course, and it does not prevent the cow being successfully vaccinated at the same time, though it appears to destroy the aptitude to receive Vaccinia ; while in two or three transmissions through the bovine species it becomes altogether impotent. The same results are observed in the horse, which, however, appears to receive the virus of human Small-pox more readily, and to exhibit more marked local phenomena than the ox ; while this inoculation also protects it partially, if not entirely, from the action of vaccine virus, which it otherwise so readily receives. As in the ox likewise, the Small-pox virus soon loses its potency in being carried from